Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
/*
ID: mchensd
LANG: JAVA
PROG: KarenAndGame
 */

/**
 *
 * @author Michael
 */

import java.util.*;
import java.io.*;

public class KarenAndGame {
    public void run(BufferedReader br, PrintWriter pw) throws IOException {
        StringTokenizer st;
        st = new StringTokenizer(br.readLine());
        int n = Integer.parseInt(st.nextToken());
        int m = Integer.parseInt(st.nextToken());
        
        int tot = 0;
        HashMap<String, Integer> hm = new HashMap<>();
        int[][] g = new int[n][m];
        int[][] curr = new int[n][m];
        for (int i=0; i<n; ++i) {
            st = new StringTokenizer(br.readLine());
            int min = 501;
            for (int j=0; j<m; ++j) {
                int next = Integer.parseInt(st.nextToken());
                g[i][j] = next;
                min = Math.min(min, next);
            }
            tot += min;
            Arrays.fill(curr[i], min);
            hm.put("row " + (i+1), min);
        }
        
//        util.print2d(curr, n, m);
//        util.print2d(g, n, m);
        for (int j=0; j<m; ++j) {
            int diff = g[0][j] - curr[0][j];
            for (int i=1; i<n; ++i) {
                if (g[i][j] - curr[i][j] != diff) {
                    pw.println(-1);
                    return;
                }
            }
            if (diff > 0) {
                hm.put("col " + (j+1), diff);
                tot += diff;
            }
        }
        
        int colTot = 0;
        int[][] currCol = new int[n][m];
        HashMap<String, Integer> hmCol = new HashMap<>();
        for (int j=0; j<m; ++j) {
            int min = 501;
            for (int i=0; i<n; ++i) {
                min = Math.min(min, g[i][j]);
            }
            hmCol.put("col " + (j+1), min);
            colTot += min;
            for (int i=0; i<n; ++i) {
                currCol[i][j] = min;
            }
        }
//        util.print2d(currCol, n, m);
        for (int i=0; i<n; ++i) {
            int diff = g[i][0] - currCol[i][0];
            for (int j=1; j<m; ++j) {
                if (g[i][j] - currCol[i][j] != diff) {
                    pw.println(-1);
                    return;
                }
            }
            hmCol.put("row " + (i+1), diff);
            colTot += diff;
        }
        
        if (tot <= colTot) {
            pw.println(tot);
            for (String s : hm.keySet()) {
                for (int i=0; i<hm.get(s); ++i) {
                    pw.println(s);
                }
            }
        }
        
        else {
            pw.println(colTot);
            for (String s : hmCol.keySet()) {
                for (int i = 0; i < hmCol.get(s); ++i) {
                    pw.println(s);
                }
            }
        }
    }
    public static void main(String[] args) throws IOException {
//        new KarenAndGame().runFileIO("KarenAndGame");
        new KarenAndGame().runStdIO();

    }
    
    public void runFileIO(String filename) throws IOException {
        BufferedReader br = new BufferedReader(new FileReader(filename + ".in"));
        PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter(filename + ".out")));
        run(br, pw);
        pw.close();
    }

    public void runStdIO() throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw = new PrintWriter(System.out);
        run(br, pw);
        pw.close();
    }
}